2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License v2 as published by
6 * the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
23 #include <arpa/inet.h>
24 #include <net/route.h>
30 static void forward_router_solicitation(const struct interface *iface);
31 static void forward_router_advertisement(uint8_t *data, size_t len);
33 static void handle_icmpv6(void *addr, void *data, size_t len,
34 struct interface *iface, void *dest);
35 static void trigger_router_advert(struct uloop_timeout *event);
36 static void sigusr1_refresh(int signal);
38 static struct odhcpd_event router_event = {.uloop = {.fd = -1}, .handle_dgram = handle_icmpv6, };
40 static FILE *fp_route = NULL;
42 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
47 int sock = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
48 if (sock < 0 && errno != EAFNOSUPPORT) {
49 syslog(LOG_ERR, "Failed to open RAW-socket: %s", strerror(errno));
53 // Let the kernel compute our checksums
55 setsockopt(sock, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val));
57 // This is required by RFC 4861
59 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
60 setsockopt(sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val));
62 // We need to know the source interface
64 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
65 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &val, sizeof(val));
69 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
71 // Filter ICMPv6 package types
72 struct icmp6_filter filt;
73 ICMP6_FILTER_SETBLOCKALL(&filt);
74 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
75 ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filt);
76 setsockopt(sock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt));
79 router_event.uloop.fd = sock;
80 odhcpd_register(&router_event);
82 if (!(fp_route = fopen("/proc/net/ipv6_route", "r")))
83 syslog(LOG_ERR, "Failed to open routing table: %s",
86 signal(SIGUSR1, sigusr1_refresh);
91 int setup_router_interface(struct interface *iface, bool enable)
93 if (!fp_route || router_event.uloop.fd < 0)
96 struct ipv6_mreq all_nodes = {ALL_IPV6_NODES, iface->ifindex};
97 struct ipv6_mreq all_routers = {ALL_IPV6_ROUTERS, iface->ifindex};
99 uloop_timeout_cancel(&iface->timer_rs);
100 iface->timer_rs.cb = NULL;
102 if (iface->ifindex <= 0)
105 setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
106 &all_nodes, sizeof(all_nodes));
107 setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
108 &all_routers, sizeof(all_routers));
112 trigger_router_advert(&iface->timer_rs);
114 void *mreq = &all_routers;
116 if (iface->ra == RELAYD_RELAY && iface->master) {
118 forward_router_solicitation(iface);
119 } else if (iface->ra == RELAYD_SERVER && !iface->master) {
120 iface->timer_rs.cb = trigger_router_advert;
121 uloop_timeout_set(&iface->timer_rs, 1000);
122 ndp_rqs_addr6_dump();
125 if (iface->ra == RELAYD_RELAY || (iface->ra == RELAYD_SERVER && !iface->master))
126 setsockopt(router_event.uloop.fd, IPPROTO_IPV6,
127 IPV6_ADD_MEMBERSHIP, mreq, sizeof(all_nodes));
133 // Signal handler to resend all RDs
134 static void sigusr1_refresh(_unused int signal)
136 struct interface *iface;
137 list_for_each_entry(iface, &interfaces, head)
138 if (iface->ra == RELAYD_SERVER && !iface->master)
139 uloop_timeout_set(&iface->timer_rs, 1000);
142 static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
144 struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
145 struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
147 /* Hoplimit is already checked in odhcpd_receive_packets */
148 if (len < sizeof(*hdr) || hdr->icmp6_code)
151 switch (hdr->icmp6_type) {
152 case ND_ROUTER_ADVERT:
153 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
156 opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
159 case ND_ROUTER_SOLICIT:
160 opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
167 icmpv6_for_each_option(opt, opt, end)
168 if (opt->type == ND_OPT_SOURCE_LINKADDR &&
169 IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
170 hdr->icmp6_type == ND_ROUTER_SOLICIT)
173 // Check all options parsed successfully
178 // Detect whether a default route exists, also find the source prefixes
179 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
183 char line[512], ifname[16];
184 bool found_default = false;
185 struct odhcpd_ipaddr p = {IN6ADDR_ANY_INIT, 0, 0, 0, 0};
186 while (fgets(line, sizeof(line), fp_route)) {
188 if (sscanf(line, "00000000000000000000000000000000 00 "
189 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname) &&
190 strcmp(ifname, "lo")) {
191 found_default = true;
192 } else if (sscanf(line, "%8" SCNx32 "%8" SCNx32 "%*8" SCNx32 "%*8" SCNx32 " %hhx %*s "
193 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32 " lo",
194 &p.addr.s6_addr32[0], &p.addr.s6_addr32[1], &p.prefix, &rflags) &&
195 p.prefix > 0 && (rflags & RTF_NONEXTHOP) && (rflags & RTF_REJECT)) {
196 // Find source prefixes by scanning through unreachable-routes
197 p.addr.s6_addr32[0] = htonl(p.addr.s6_addr32[0]);
198 p.addr.s6_addr32[1] = htonl(p.addr.s6_addr32[1]);
200 for (ssize_t i = 0; i < len; ++i) {
201 if (n[i].prefix <= 64 && n[i].prefix >= p.prefix &&
202 !odhcpd_bmemcmp(&p.addr, &n[i].addr, p.prefix)) {
203 n[i].dprefix = p.prefix;
211 return found_default;
214 static int calc_adv_interval(struct interface *iface, uint32_t minvalid,
217 uint32_t minival = iface->ra_mininterval;
220 *maxival = iface->ra_maxinterval;
222 if (*maxival > minvalid/3)
223 *maxival = minvalid/3;
225 if (*maxival > MaxRtrAdvInterval)
226 *maxival = MaxRtrAdvInterval;
227 else if (*maxival < 4)
230 if (minival < MinRtrAdvInterval)
231 minival = MinRtrAdvInterval;
232 else if (minival > (*maxival * 3)/4)
233 minival = (*maxival >= 9 ? *maxival/3 : *maxival);
235 odhcpd_urandom(&msecs, sizeof(msecs));
236 msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) +
242 static uint16_t calc_ra_lifetime(struct interface *iface, uint32_t maxival)
244 uint16_t lifetime = 3*maxival;
246 if (iface->ra_lifetime >= 0) {
247 lifetime = iface->ra_lifetime;
248 if (lifetime < maxival)
250 else if (lifetime > 9000)
268 // Router Advert server mode
269 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
271 time_t now = odhcpd_time();
272 int mtu = iface->ra_mtu;
273 int hlim = iface->ra_hoplimit;
276 mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
282 hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
285 struct nd_router_advert h;
286 struct icmpv6_opt lladdr;
287 struct nd_opt_mtu mtu;
289 .h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0},
290 .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
291 .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
295 adv.h.nd_ra_curhoplimit = hlim;
298 adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
300 if (iface->managed >= RELAYD_MANAGED_MFLAG)
301 adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
303 if (iface->route_preference < 0)
304 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
305 else if (iface->route_preference > 0)
306 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
308 adv.h.nd_ra_reachable = htonl(iface->ra_reachabletime);
309 adv.h.nd_ra_retransmit = htonl(iface->ra_retranstime);
311 odhcpd_get_mac(iface, adv.lladdr.data);
313 // If not currently shutting down
314 struct odhcpd_ipaddr *addrs = NULL;
316 uint32_t minvalid = UINT32_MAX;
317 bool default_route = false;
318 bool valid_prefix = false;
321 if (iface->timer_rs.cb) {
322 size_t size = sizeof(*addrs) * iface->ia_addr_len;
323 addrs = alloca(size);
324 memcpy(addrs, iface->ia_addr, size);
326 ipcnt = iface->ia_addr_len;
328 // Check default route
329 if (iface->default_router) {
330 default_route = true;
332 if (iface->default_router > 1)
334 } else if (parse_routes(addrs, ipcnt))
335 default_route = true;
339 struct in6_addr dns_pref, *dns_addr = &dns_pref;
342 odhcpd_get_interface_dns_addr(iface, &dns_pref);
344 // Construct Prefix Information options
346 struct nd_opt_prefix_info *pfxs = NULL;
348 for (ssize_t i = 0; i < ipcnt; ++i) {
349 struct odhcpd_ipaddr *addr = &addrs[i];
350 uint32_t preferred = 0;
353 if (addr->prefix > 96 || addr->valid <= (uint32_t)now) {
354 char namebuf[INET6_ADDRSTRLEN];
356 inet_ntop(AF_INET6, addr, namebuf, sizeof(namebuf));
357 syslog(LOG_INFO, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s",
358 namebuf, addr->prefix, addr->valid, iface->ifname);
362 struct nd_opt_prefix_info *p = NULL;
363 for (size_t i = 0; i < pfxs_cnt; ++i) {
364 if (addr->prefix == pfxs[i].nd_opt_pi_prefix_len &&
365 !odhcpd_bmemcmp(&pfxs[i].nd_opt_pi_prefix,
366 &addr->addr, addr->prefix))
371 struct nd_opt_prefix_info *tmp;
373 tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1));
375 syslog(LOG_ERR, "Realloc failed for RA prefix option on interface %s", iface->ifname);
380 p = &pfxs[pfxs_cnt++];
381 memset(p, 0, sizeof(*p));
384 if (addr->preferred > (uint32_t)now) {
385 preferred = TIME_LEFT(addr->preferred, now);
387 if (iface->ra_useleasetime &&
388 preferred > iface->dhcpv4_leasetime)
389 preferred = iface->dhcpv4_leasetime;
392 valid = TIME_LEFT(addr->valid, now);
393 if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
394 valid = iface->dhcpv4_leasetime;
396 if (minvalid > valid)
399 if (!IN6_IS_ADDR_ULA(&addr->addr) || iface->default_router)
402 odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr,
403 (iface->ra_advrouter) ? 128 : addr->prefix);
404 p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
405 p->nd_opt_pi_len = 4;
406 p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
407 p->nd_opt_pi_flags_reserved = 0;
408 if (!iface->ra_not_onlink)
409 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
410 if (iface->managed < RELAYD_MANAGED_NO_AFLAG && addr->prefix <= 64)
411 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
412 if (iface->ra_advrouter)
413 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
414 p->nd_opt_pi_preferred_time = htonl(preferred);
415 p->nd_opt_pi_valid_time = htonl(valid);
418 // Calculate periodic transmit
420 int msecs = calc_adv_interval(iface, minvalid, &maxival);
424 syslog(LOG_WARNING, "A default route is present but there is no public prefix "
425 "on %s thus we don't announce a default route!", iface->ifname);
426 adv.h.nd_ra_router_lifetime = 0;
428 adv.h.nd_ra_router_lifetime = htons(calc_ra_lifetime(iface, maxival));
431 adv.h.nd_ra_router_lifetime = 0;
433 syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->ifname);
436 if (iface->dns_cnt > 0) {
437 dns_addr = iface->dns;
438 dns_cnt = iface->dns_cnt;
441 if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
450 } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, 0};
452 // DNS Search options
453 uint8_t search_buf[256], *search_domain = iface->search;
454 size_t search_len = iface->search_len, search_padded = 0;
456 if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
457 int len = dn_comp(_res.dnsrch[0], search_buf,
458 sizeof(search_buf), NULL, NULL);
460 search_domain = search_buf;
466 search_padded = ((search_len + 7) & (~7)) + 8;
475 } *search = alloca(sizeof(*search) + search_padded);
477 search->type = ND_OPT_DNS_SEARCH;
478 search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
481 memcpy(search->name, search_domain, search_len);
482 memset(&search->name[search_len], 0, search_padded - search_len);
485 size_t routes_cnt = 0;
493 } *tmp, *routes = NULL;
495 for (ssize_t i = 0; i < ipcnt; ++i) {
496 struct odhcpd_ipaddr *addr = &addrs[i];
497 if (addr->dprefix > 64 || addr->dprefix == 0 || addr->valid <= (uint32_t)now ||
498 (addr->dprefix == 64 && addr->prefix == 64)) {
499 continue; // Address not suitable
500 } else if (addr->dprefix > 32) {
501 addr->addr.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1));
502 } else if (addr->dprefix <= 32) {
503 addr->addr.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1));
504 addr->addr.s6_addr32[1] = 0;
507 tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1));
509 syslog(LOG_ERR, "Realloc failed for RA route option on interface %s", iface->ifname);
515 memset(&routes[routes_cnt], 0, sizeof(*routes));
516 routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
517 routes[routes_cnt].len = sizeof(*routes) / 8;
518 routes[routes_cnt].prefix = addr->dprefix;
519 routes[routes_cnt].flags = 0;
520 if (iface->route_preference < 0)
521 routes[routes_cnt].flags |= ND_RA_PREF_LOW;
522 else if (iface->route_preference > 0)
523 routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
524 routes[routes_cnt].lifetime = htonl(TIME_LEFT(addr->valid, now));
525 routes[routes_cnt].addr[0] = addr->addr.s6_addr32[0];
526 routes[routes_cnt].addr[1] = addr->addr.s6_addr32[1];
527 routes[routes_cnt].addr[2] = 0;
528 routes[routes_cnt].addr[3] = 0;
533 search->lifetime = htonl(maxival*10);
534 dns.lifetime = search->lifetime;
536 struct icmpv6_opt adv_interval = {
537 .type = ND_OPT_RTR_ADV_INTERVAL,
539 .data = {0, 0, (maxival*1000) >> 24, (maxival*1000) >> 16, (maxival*1000) >> 8, maxival*1000}
542 struct iovec iov[IOV_RA_TOTAL] = {
543 [IOV_RA_ADV] = {&adv, sizeof(adv)},
544 [IOV_RA_PFXS] = {pfxs, pfxs_cnt * sizeof(*pfxs)},
545 [IOV_RA_ROUTES] = {routes, routes_cnt * sizeof(*routes)},
546 [IOV_RA_DNS] = {&dns, (dns_cnt) ? sizeof(dns) : 0},
547 [IOV_RA_DNS_ADDR] = {dns_addr, dns_cnt * sizeof(*dns_addr)},
548 [IOV_RA_SEARCH] = {search, search->len * 8},
549 [IOV_RA_ADV_INTERVAL] = {&adv_interval, adv_interval.len * 8}};
550 struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
552 if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
553 dest.sin6_addr = *from;
555 odhcpd_send(router_event.uloop.fd,
556 &dest, iov, ARRAY_SIZE(iov), iface);
565 static void trigger_router_advert(struct uloop_timeout *event)
567 struct interface *iface = container_of(event, struct interface, timer_rs);
568 int msecs = send_router_advert(iface, NULL);
570 // Rearm timer if not shut down
572 uloop_timeout_set(event, msecs);
576 // Event handler for incoming ICMPv6 packets
577 static void handle_icmpv6(void *addr, void *data, size_t len,
578 struct interface *iface, _unused void *dest)
580 struct icmp6_hdr *hdr = data;
581 struct sockaddr_in6 *from = addr;
583 if (!router_icmpv6_valid(addr, data, len))
586 if ((iface->ra == RELAYD_SERVER && !iface->master)) { // Server mode
587 if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
588 send_router_advert(iface, &from->sin6_addr);
589 } else if (iface->ra == RELAYD_RELAY) { // Relay mode
590 if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
591 forward_router_advertisement(data, len);
592 else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master)
593 forward_router_solicitation(odhcpd_get_master_interface());
598 // Forward router solicitation
599 static void forward_router_solicitation(const struct interface *iface)
604 struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
605 struct iovec iov = {&rs, sizeof(rs)};
606 struct sockaddr_in6 all_routers =
607 {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, iface->ifindex};
609 syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname);
610 odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface);
614 // Handler for incoming router solicitations on slave interfaces
615 static void forward_router_advertisement(uint8_t *data, size_t len)
617 struct nd_router_advert *adv = (struct nd_router_advert *)data;
620 uint8_t *end = data + len;
621 uint8_t *mac_ptr = NULL;
622 struct in6_addr *dns_ptr = NULL;
623 size_t dns_count = 0;
625 struct icmpv6_opt *opt;
626 icmpv6_for_each_option(opt, &adv[1], end) {
627 if (opt->type == ND_OPT_SOURCE_LINKADDR) {
628 // Store address of source MAC-address
630 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
631 // Check if we have to rewrite DNS
632 dns_ptr = (struct in6_addr*)&opt->data[6];
633 dns_count = (opt->len - 1) / 2;
637 syslog(LOG_NOTICE, "Got a RA");
639 // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
640 adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY;
642 // Forward advertisement to all slave interfaces
643 struct sockaddr_in6 all_nodes = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
644 struct iovec iov = {data, len};
646 struct interface *iface;
647 list_for_each_entry(iface, &interfaces, head) {
648 if (iface->ra != RELAYD_RELAY || iface->master)
651 // Fixup source hardware address option
653 odhcpd_get_mac(iface, mac_ptr);
655 // If we have to rewrite DNS entries
656 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
657 const struct in6_addr *rewrite = iface->dns;
658 struct in6_addr addr;
659 size_t rewrite_cnt = iface->dns_cnt;
661 if (rewrite_cnt == 0) {
662 if (odhcpd_get_interface_dns_addr(iface, &addr))
663 continue; // Unable to comply
669 // Copy over any other addresses
670 for (size_t i = 0; i < dns_count; ++i) {
671 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
672 dns_ptr[i] = rewrite[j];
676 odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface);